This study reported the effect of Eu substitutions on the conductivity and dielectric properties of Y3-xEuxAl5O12 (0.0x0.1), YAG:xEu(3+). All products were fabricated by solid state route. The formation of YAG was approved through X-ray diffraction powder diffraction and high-resolution transmission electron microscope. It was found that the lattice parameters are increasing with increase the substitution content due to the difference in ionic radii between Y3+ and Eu3+. Electrical and dielectric properties of YAG (Y3Al5O12) and YAG:xEu(3+) ceramics were investigated extensively for a variety of concentrations (0.00x0.1) of the substitutional Eu3+ ion from the 4f lanthanide group. The temperature dependence of dielectric loss, dielectric constant, loss tangent and ac/dc conductivity were examined up to 5.0MHz to understand the electrical and dielectric properties for both doped and undoped YAG ceramics. The experimental results revealed that Eu3+ ion substitutions (especially x=0.05) in YAG ceramics meaningfully influence the lossy mechanisms, conductivity and dielectric constant which is probably due to the contribution to the conduction mechanism of the 4f-Eu and 3d-Al ions. So, this can be incorporated at the exceptional sites of both O-h (octahedral) and T-d (tetrahedral) symmetries in YAG: xEu(3+) ceramics.